The present invention concerns a window lifter, a controlling device of a window lifter and a method to control the window lifter. The present application may be applied to other moving parts of a motor vehicle including a hatchback, sun roof and the like.
A method for the control and regulation of the adjusting movement of a translational adjustable component, especially of a window lifter of a power window in motor vehicles, is known in the art from the DE 197 45 597 A1. The method considers the driving device as well as the control and regulating electronics. Accordingly, an effective squeeze protection is obtained which considers sufficient regulating power in difficult areas and the body of the vehicle along with external conditions, forces and influences. The driving device exercises such regulating power, the power being equal to the sum of superfluous power and necessary power to adjust the component, whereby the sum is less or equal to the acceptable squeezing power. The regulating or superfluous power is additionally regulated with respect to the forces effecting the body of the vehicle or parts thereof.
The aforementioned solution substantially guarantees a squeeze protection affecting the entire regulation area, thereby being in compliance with very high protection requirements or regulations. In addition, it is guaranteed that the regulating power is sufficient in restricted areas; and that a regulating device adjusts a translational adjustable component, gently with respect to the material, so as to consider the external influences affecting the body of the vehicle according to the mass-giving operator. The forces affecting the body of the vehicle or the acceleration forces are herein understood as being external influences which are not immediately caused by the regulating device or by a driving device, but which occur for example because of the bad conditions of the driving route (e.g. driving over a pothole) or during the closing of a vehicle door.
It is additionally provided, that a regulation of the regulating power or the superfluous power is interrupted during the occurrence of acceleration forces affecting the body of the vehicle and within a changing preset time frame and a threshold value is preset in such a way, that the regulating power is always less or even to the acceptable squeezing force. The time frame may be for example 100 ms. This form of execution considers that the threshold value is not always changed within a short time frame at always changing acceleration forces affecting the body of the vehicle, which in turn could lead to an impairment of the movement of the translational adjustable component. A secure movement of the translational adjustable component is guaranteed also as squeeze protection by the preset threshold value, which is always less or even to the acceptable squeezing force.
The acceleration forces affecting the body of the vehicle are preferably detected by a sensor, such as for example a digital signal sensor. Digital signals can be easily further processed in the control and regulation electronics. The adjustment of one or more regulations, in successively connecting signals of the sensor, can be evaluated by the control and regulation electronics. The repeated valuation of the signals of the sensor enables one to securely identify a simultaneous occurrence of the acceleration forces caused by external influences and the forces conditional in the event of squeezing.
A motor driving device for a motor vehicle is known in the art from DE 195 17 958. The rotation of the motor is immediately stopped, at the motor driving device, for an electrical window lifter, when an obstacle is placed against the movement of the window. The motor driving device serves to open and close the moveable part (window) and can be selectively turned on and off.
An electrical current meter device measures the current conducting by the motor at a start compensation time; an intensity changing detector detects an intensity increment from the measured current at each constant time frame; and a motor controlling device delivers a first or a second control signal to the motor driving device whereby the motor operation is continued with the first signal depending on the polarity of the intensity increment and the motor immediately stopped with the second signal.
Two monitoring switches mark the rotating direction of the motors, a pair of touch-buttons for the correspondent motor directions and two self-holding switches for the two rotational directions of the motors enable a rotation of the motor at operation of one of the touch-buttons.
A control device for power locks is known in the art from DE 196 49 698. The control device is independent from its configuration and can be operated in different ways directly and by a distance switch. Security measures use an adjustment strategy to enable a highly sensitive detection of an impediment by, for example, learning the power requirements of the system and equipping it within a safety margin. The control system allows a complete manual operation of the lockage.
Information about the operational power which is necessary at each point of the motion path of the rear flap along its predetermined motion path to close the rear flap is stored. Values are stored in four multi-dimensional arrangements. The dimensions of the arrangement are motion direction and position. The motion direction is open and close. The position is any number of divisions of the specified path. The following are determined: the operating force (fmem); the time derivation of the operating force (dfmem); the fluctuations of the operating force measurements (vfmem); and the fluctuation of the measurements of the derivation of the operating force after the time (vdfmem). Further stored values include the number of the rear flap opening and closing actions without the detection of an obstacle, the number of the detected obstacles, and the average operating force over the last n minutes.
The operation of the rear flap occurs at time t, at which time the rear flap is located in the area p along its predetermined path, and the motion direction of the rear flap is d. The storage values are used for the detection of an obstacle as follows:
The measured force of the first operating device is compared with the power arrangement for the present rear flap position and direction with a system-dependant combination of the following conditions.                The present force (f(d,t)) is greater than the force stored in the storage for this rear flap position (fmem(d,p)), i.e. by a deviation (fmargin(d)).        The present derivation of the force according to the time (df/dt(d,t)) is greater than the time deviation of the force, which is stored in the storage for this rear flap position (dfmem(d,p)), i.e. by a deviation (dfmargin(d)).        The present force (f(d,t)) is greater than a predetermined absolute maximal force (fmax(d)). This maximal force is a maximum, which must not be exceeded under any circumstances.        
The deviation is thereby adjustable. In addition, the tolerance (fmargin as well as dfmargin) can be designed as a function of vfmem(d,p) and vdfmem(d,p). This means, that the tolerance itself is a function of the position and varies at each position with time when the force varies. As such, the tolerance is also increased with an increase of the temporary or local change of the force.
If the force at position d,p is the same at each cycle, the tolerance becomes lower and the system more sensitive. If the force at the position d,p is significantly different during each run, the tolerance may tend to remain high. The tolerance is limited so that it can not grow beyond a certain point with an indication of tolerance increase beyond its limit being a basis for indication of a system error.
In addition, to change the stored forces (either one or both of fmem(p) and dfmem(p)) as function of any external sensor (for example a temperature sensor) may be considered or known to anticipate environmental influences.
If the arrangements contain valid data, and the control device does not detect an obstacle during the rear flap motion, the values are adjusted according to the following formulas:Fmem(d,p)=(k1×f(d,p)+k2×fmem(d,p)/k1+k2 Dfmem(d,p)=(k3×df/dt(d,p)+k4×dfmem(d,p)/k5+k6 Vfmem(d,p)=(k5×(f(d,p)−fmem(d,p)+k6×vfmem(d,p)/k5+k6 Vdfmem(d,p)=(k7×(f(d,p)−fmem(d,p)+k8×vfmem(d,p)/k7+k8 Whereby k1, k2, k3, k4, k5, k6, k7 and k8 are determined empirically in dependence from the dynamics of the system. Accordingly, an increasing temporal change to the previous dfmem(d,p) leads to an increase of the new and current dfmem(d,p). k1, k2, k3, k4, k5, k6, k7 and k8 influence the speed with which the system learns and therefore, how the system responds to a changing environment. These values are typically selected in such a way that k1, k3, k5 and k7 are much smaller than k2, k4, k6 and k8.